From 0 to Hero...

[maddogrc]

well today while its around 25 celsius i've done a few tests.

firstly i reset my ecu with the stock filter system on, worked amazing

secondly i reset my ecu and put on the 3 inch pod air intake, didnt work as great as stock

thirdly i reset my ecu and then ran the 3 inch pod air intake system, but i remounted the maf sensor in the pipe, didnt work as great as stock

fourth i reset my ecu and ran the 3 inch pod air intake with the maf sensor hanging from the side of the car allowing air flow directly into it, didnt work as great as stock

and finally fifth, i reset my ecu and put the stock system on, worked amazing!

interesting results i reckon, especially the mod intake with the maf sensor getting direct flow and not being as great.

well i'm sticking to the stock system for now and going to flog the 3 inch system to a friend, haha

only good thing about the 3 inch pod is that when you shift it goes pssssht XD i know i know, but i'm only young and this is my first car

 

[D22 King]

yeh reset the ecu today and put some 265/75/16s on and still had more get up and grunt then standard tyres

 

[Dion]

Pod filter undersized, maybe? The other thing I was thinking, the MAF needs laminar flow and the factory system will be designed to create that, whilst the three inch system isn't. Anyway, I'll shut up now.

 

[maddogrc]

nah, its a typical sized one, but no monster 8 inch outlet one, lol

what you mean by laminar flow?

 

[tkingcab]

the detuned d22 run different injectors as far as i know because chips are different for d22 and d40 both have different end powers and torques. Your pod setup could of been not letting maf sensor pick up correct air measurements and when u put it all back to standard it could read properly

 

[maddogrc]

i also ran a test where i had the maf sensor in DIRECT air flow by not being in the pod set up, and it still acted the same

 

[Dion]

nah, its a typical sized one, but no monster 8 inch outlet one, lol

what you mean by laminar flow?

Well, for a basic approximation consider a comparison of the surface area of the factory and pod filters. However, unless it's seriously undersized you shouldn't expect a large enough pressure drop to cause the symptoms you described.

From the process you described a few posts ago, it sounds like the deciding factor is definitely the intake setup. Which leads me to the laminar flow. Normally I'd think it was a bit finnicky and I'm sure Tweak'e will call me overly theoretical again, but it's fairly widely published that you'll get false readings from a MAF not placed in laminar flow.

Laminar fluid flow is where the streamlines are parallel. For a good example of fluid flow types, watch a cigarette burning. When the smoke comes off the burning tip, it is laminar. It then begins to break up (called transitional flow) and finally, twirls, curls, and generally moves randomly (called turbulent flow). Since the MAF sensor operates on the principle that the air flow moving past the hot wire cools it increasing the resistance, turbulent flow would not provide accurate data about the air flow as, at times, the air around the MAF sensor will be moving slower, faster, not moving, generally random. Put turbulent and laminar in a youtube search.

So, it is possible to control with design the type of flow in a given environment and my bet is Nissan has designed their intake system to present laminar flow to the MAF sensor for correct readings and the best air-fuel ratio. It is possible to easily resume laminar pipe flow with a long section of straight pipe, but Nissan will have done something more tricky.

 

[tkingcab]

oh ok so was in stock location? I could be totally wrong i just know some cars hate pod filters even with maf sensor in stock location

 

[Dion]

i also ran a test where i had the maf sensor in DIRECT air flow by not being in the pod set up, and it still acted the same

That's guaranteed to give you completely incorrect readings, but it's an interesting experiment.

 

[tkingcab]

thanks
Pro nav for writing what i was too lazy

 

[maddogrc]

i also know that if u blow on the maf sensor that the engine note changes for the time that u blow air from your breath onto it.

it didnt make the idle go up or anything, it just changed the sound of the engine for that moment, but it was noticeable easily

 

[Dion]

oh ok so was in stock location? I could be totally wrong i just know some cars hate pod filters even with maf sensor in stock location

I can see laminar flow leaving an airbox - I can't see it leaving a pod filter. But don't tell anyone, I'd hate for Supercheap Auto to go out of business.

Haha, no worries tkingcab.

 

[maddogrc]

oh ok so was in stock location? I could be totally wrong i just know some cars hate pod filters even with maf sensor in stock location

i mentioned it on the previous page before i think that i mounted the pod filter into the stock air box to act as the stock filter, and the car acted like it did with the stock filter?

very interesting...

 

[Dion]

i also know that if u blow on the maf sensor that the engine note changes for the time that u blow air from your breath onto it.

it didnt make the idle go up or anything, it just changed the sound of the engine for that moment, but it was noticeable easily

Really?? Sweet as! I'm gonna do that party trick heaps from now on. Makes sense.

 

[Dion]

i mentioned it on the previous page before i think that i mounted the pod filter into the stock air box to act as the stock filter, and the car acted like it did with the stock filter?

very interesting...

That means the pod is close enough to the right size. I think the factory airbox and factory plumbing induces the laminar flow required.

 

[tkingcab]

Yeah thats strange im not familiar with ur airbox how did u connect it inside airbox i didn think it would just slip on

 

[maddogrc]

pretty much the stock air box works by forcing inducted air through 1 side of the cylinder shaped paper type filter, and having it flow through to the inside/centre of the cylinder and then go through a plastic sorta fitting for where the filter sits and the maf sensor is just after the filter.

 

[Dion]

Any chance you could pull the clips open and photograph the inside of the engine side airbox cover, looking into the intake pipe with the MAF sensor in view if possible?

 

[maddogrc]

there ya go mate!

 

[Dion]

Hmm. Hard to tell how it's made laminar there, may be related to the filter. If you can be bothered, take a photo of the filter looking through it.

Moral of the story, the factory intake on your model engine is fine.